Calculator.



No. 555,553. Patented Aug. '7, I900.

a. J. GNAU.

CALCULATOR.

(Application filed Oct. 28, 1899.)

(N0 llodal.)

Ian 071662" 2 7e J7vww THE Nonms PETERS co., PHoTo-uma, WASHINGYON, D40.

r-TED TATES PATENT OFFICE.

GEORGE J. GNAU, OF DETROIT, MICHIGAN.

CALCU LATOR.

SPECIFICATION forming part of Letters Patent No. 655,653, dated August'7, 1900.

Application filed October 28, 1899. $erial No. 734,571. (No model.)

To all whom, it may cancer-n.-

Be it known that I, GEORGE J. GNAU, a citizen of the United States,residing at Detroit, in the county of Wayne and State of Michigan, haveinvented certain new and useful Improvements in Calculators, of whichthe following is a specification, reference being had therein to theaccompanying drawings.

The invention relates generally to calculators,and has particularreference to a machine of this type especially designed for computingthe wages of employees for any number of hours, days, or parts thereof.

The invention consists in the novel constructionof a calculator of thistype and in the peculiar arrangement, construction, and combination ofits various parts, all as more fully hereinafter described, and shown inthe drawings, in which- Figure 1 is a perspective View of thecalculator. Fig. 2 is a vertical central section therethrough. Fig. 3 isan enlarged sectional view of a portion of the mechanism shown in Fig.2. Fig. 4 is an enlarged front elevation of the computing portion of thecalculator. Fig. 5 is a view of the calculator with the front of thecasing removed, showing the formation of the computing-disks; and Fig. 6is a section on line 00 :0, Fig. 2.

In construction the calculator consists, essentially, of an inclosedcasing having a segmental opening or radial slot formed in the frontthereof and provided at one or both sides of the opening with a columnof factors of value, one or more disks mounted for rotary movementwithin the casing and having radial columns of computations thereonadapted to be viewed through the casingopening, and means for rotatingthe disks independently to bring the radial columns thereon in readingrelation to the column or columns on the casing-front.

More particularly the construction of the calculator is as follows:

The reference-letter A designates the inclosing casing, which ispreferably semicircular or su bstantially semicircular in configurationto allow of its being arranged upon a desk or table in convenientrelation to the operator.

B designates a supporting-arm hinged to the casing-back 0, adapted tomaintain the casing in a substantially upright position upon its flatside orbase D. The casing-front is slotted radially, as at E, theopening being substantially the segnlent of a circle, and upon one orboth sides of said radial opening is a series of factors designating therate of Wages per week or the rate per day, or both, as plainly shown inFig. 4. I also preferably mark above these columns suitable lettering,as Week rate or Day rate, to indicate What the particular factors are,and upon the portion of the casing immediately above the radial slot ismarked the Word Hours. The front and back covers F and O of the casingare each apertured, as at b and a, and secured to the covers are theapertured bearingplates 0 and d, the plates being so arranged that theapertures therein will register with the apertures in the covers.

The reference-letter F designates a sleeve journaled within theapertured cover F and extending some distance Within the casing. Uponthis sleeve is secured in any suitable manner, as by brazing, a flangedsleeve or thimblef, as plainly shown in Fig. 3, and I designates anouter disk fixedly secured in any suitable manner to the flanged portionof the thimble. This disk is provided with a ra dial slot similar information and size to the segmental opening in the casing-front, and hasmarked upon its periphery factors of time in hours or parts thereof from1% to 27117. Beneath each factor of time is arranged a radial column ofcomputations of value designating the amount of wages due at differentrates per week for the period of time above the column.

H designates a thumb-nut which is adapted to be threaded upon theportion 7a of the sleeve which extends beyond the front of the casing,whereby the disk may be rotated to bring the columns of computationsthereon in reading relation to the column upon the side of the slot inthe casing-front.

In order that wages may be computed for a longer period than ispermissible by the use of a single disk, I have provided a second orinner disk G within the casing, marked in a similar manner to the outerdisk, but of greater diameter than said latter disk in order that theperipheral marking thereon will not be covered by the outer disk. Uponthe periphery the factors of time are arranged in the same manner, butare a continuation of the factors upon the outer disk, commencing inthis particular case with 28 and reading in whole numbers and fractionsto 54: 3.

The disk just described is mounted for retary movement within the casingand is provided with means for operating the same independently of thecomplementary disk, as follows:

The reference-letter J designates a spindle which is journaled withinthe sleeve F and extends through and beyond the outer disk carried bysaid sleeve and likewise projects some distance beyond the thumb-nutupon the sleeve. At its inner end the spindle is reduced in diameter, asatj, and has a hearing within the apertured back cover of the casing, asplainly shown in Fig. 3. Upon the reduced portion is brazed or securedin any suitable manner a thimble 7t, similar in construction to thethimble before described, and to this thimble is attached the innerdisk, the securing devices being of any preferable type. A thumb-nut Lhas a threaded engagement with the portion of the spindle that projectsbeyond the nut II to permit of the inner disk being rotatedindependently.

The construction of my calculator having been thus set forth, theoperation of the same is as follows: Supposing that it is desired tocalculate the amount due an employee who is paid at the rate of fifteendollars per week for a period of one hour, to ascertain the amount theouter disk is rotated until the factor of time required-via, one hour-isbrought to view within the radial opening in the casing-front. Theoperator next finds the rate per week in the column upon the casingadjacent the opening that is required viz., fifteenand the computationin the ra dial column' upon the outer disk adjacent to the numerals 15will give the desired amount. In cases where the amount that is to becomputed is for a greater number of hours than appear upon the outerdisk the segmental opening in said outer disk is brought intocoincidence with the opening in the casing-front. This permits theradial columns upon the inner disk to be seen, and the operation abovedescribed is repeated, the number of hours being first found and theradial column beneath the factor of time being placed in readingrelation with the columns upon the casing-front. In order that thecalculator may be operated rapidly, I have provided means whereby theouter disk will be held stationary when the openings in the latter andthe casing are in coincidence to permit of a rapid reading upon theinner disk. The means referred to are in the form of afriction-lock,which is of very simple construction, consisting,essentially, of a depending finger Z,which projects downwardly from thecasing-top m between the outer and inner disks, and lugs o 0 upon therear face of the outer disk and on the periphery of the latter spacedfrom each other sufficiently to permit of their engagement upon theopposite sides of the depending finger. The lugs are arranged directlyabove the radial opening in the outer disk in order that the latteropening and the casing-opening will be in coincidence.

It will be readily observed from the description of my invention thatfactors for any period of time may be arranged upon the easing-frontadjacent to the opening therein and also that the day rate which I haveshown may be entirely dispensed with, if desired. I merely employ thesame as a matter of convenience to dispense with the manipulation of thecalculator when only the amount per day is to be figured.

What I claim as my invention is- 1. In a calculator, the combination ofan inclosing casing having a segmental opening formed in the frontthereof, and provided upon one side of said opening with a column offactors of value, an outer disk rotatably mounted within the casing,provided with a segmental opening corresponding to the opening in thecasing-front, and having marked upon its periphery factors of time, andbelow each of said factors a radial column of computations of value, aninner disk of greater diameter than the outer disk, having markingsthereon similar to those on the latter disk, a friction mechanism forholding the opening in the outer disk in coincidence with thecasing-opening, comprising a depending finger extending downwardly fromthe inner face of the casing-top to and between the disks, and spacedlugs upon the outer disk above the radial opening adapted to engage uponopposite sides of said finger, and means for rotating the disksindependently of each other in the manner and for the purpose described.

2. In a calculator, the combination of an. inclosing casing providedwith front and rear covers, bearing-plates thereon, a spindle journaledat its inner end in the inner bearingplate and projecting through theouter plate, a disk secured to the inner end of the spindle, a sleevejournaled on the spindle and in the outer bearing-plate, a disk securedto the inner end of the sleeve, and actuating-heads detachably securedto the outer ends of said spindle and sleeve.

In testimony whereof I affix my signature in presence of two witnesses.

GEORGE .I. GNAU.

Witnesses:

L. J. Wnrrrnnonn, II. 0. SMITH.

ICC

